As Tennis Stats Proliferate, Software Tries to Make Sense of It All

When fans think of statistics, baseball, football and basketball often come to mind first. But motion-capture cameras and other automated technologies are ubiquitous enough that a sport like tennis is being overrun with data not only on aces, double faults and first-serve percentages, but also on more subtle statistics like break-point conversions, net approaches and unforced errors.

Hard-core tennis fans may enjoy being peppered with the numbers, but casual fans may wonder how they relate to the match they are watching. I.B.M., a sponsor of the sport’s four Grand Slam tournaments, has tried to bridge that information gap with SlamTracker, software that sifts through two decades of data to predict how players could perform under various circumstances.

Since 2011, SlamTracker has also provided television announcers with specific statistical talking points — called Keys to the Match — to refer to before and during matches. When Novak Djokovic plays Roger Federer, the announcers can note that, according to SlamTracker, Djokovic’s chances of winning will rise if he plays sustained rallies, and Federer stands a better chance if his serves are sharp. The keys are updated during matches to track any shift in momentum, and they correlate well with the final outcome, said John Kent, who oversees SlamTracker for I.B.M.

The findings may sound elementary, but they are based on more than 8,000 matches I.B.M. has cataloged in the past eight years at the four Grand Slam events. In all, SlamTracker’s Keys to the Match are based on more than 41 million data points, including scores, match duration, winners, serve speed, number and types of shots and serve percentages. Some of the data, like serve speed, is tallied instantly by machines. Other figures are compiled by umpires and courtside statisticians.

Fans who watch the United States Open and the other three major tournaments on television have most likely seen SlamTracker’s Keys to the Match, where the announcers not only recite the information before matches, but refer to I.B.M.’s predictive analysis during them.

“You pick one or two patterns in the match and see what’s trending,” said Tracy Austin, an analyst for Tennis Channel who won two United States Open singles titles. “If she is starting to change her game, I need to tell the viewer.”

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The U.S. Open iPad app.Credit
USTA

There are limitations. Announcers are not supposed to talk right before serves and during points, which restricts how much information can be conveyed. And while there are plenty of statistics, announcers try to focus on break points and other critical junctures, which may not arise frequently in a lopsided match.

“Tennis has been behind the eight ball, and we’re just starting to catch up,” said Patrick McEnroe, a television analyst and the general manager for player development at the United States Tennis Association. But “in the broadcast world, we don’t have a ton of time.”

Fans at home can gain access to much of this information on their computers, tablets and smartphones. Given the growing number of Wi-Fi and cellphone connections at sports arenas, fans can view it while watching matches in person, too.

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Like teams and leagues in other sports, the U.S.T.A., which runs the Open, has tried to give fans in attendance as much information as they would receive at home, if not more. A large scoreboard near Arthur Ashe Stadium showcases various pieces of data on the day’s matches, and I.B.M. has adapted SlamTracker for iPads, Android smartphones and other devices.

“It speaks to the need to always fulfill the fans’ desire for deeper knowledge,” said Nicole Jeter West, director of digital strategy and partnerships at the U.S.T.A. “There is a constant desire for the fan to have more and more information and make it bite-size.”

This year, I.B.M. has expanded SlamTracker to include a social sentiment function so fans can analyze not just how the players are doing, but also see what other fans are talking about. This might include, say, running commentary on Twitter about a player’s outfit or a marathon match on Court 17.

These extra features are likely to drive traffic to the event’s Web site, USOpen.org, and its various mobile versions. The number of page views on USOpen.org’s mobile site grew by 38 percent last year.